Dense γ-ray emission in two consecutive pulses irradiating near critical density plasma

Abstract

We report the overdense electron acceleration and dense gamma ray emission via using two continuous laser pulses irradiating near critical density plasma. Thanks to the ion channel formed behind the first laser pulse, the leading laser beam is well focused to a higher intensity. As a result, the noticeable electron re-injection and ion focusing when one laser incident is significantly suppressed in the two consecutive lasers scheme, which efficiently improved the electron acceleration process. Moreover, owing to the stronger laser field and the higher electron energy, the probability rate of emitting γ-ray by the accelerated electron is considerably enhanced. In this regime, the laser intensity is reduced from 1 × 1023 W cm−2 to 4 × 1022 W cm−2 with the competitive density of generated gamma rays.